1. Field of the Invention
The present invention relates to light source devices, more particularly to a light source device for irradiating a document with light.
2. Description of Related Art
As a conventional light source device, for example, a lighting device described in Japanese Patent Laid-Open Publication No. 2002-185708 is known. FIG. 7 is a configuration diagram of the lighting device 500 described in Japanese Patent Laid-Open Publication No. 2002-185708.
The lighting device 500 described in Japanese Patent Laid-Open Publication No. 2002-185708 includes a light guide 502 and a light source 504. The light guide 502 is U-shaped. The light source 504 is provided at one end of the light guide 502. Light emitted by the light source 504 is guided along the U-shaped light guide 502, from one end to the other, and is also directed to a document placed on the lighting device 500. As a result, the document is irradiated with light from two directions. In the lighting device 500 as described above, the document is irradiated with light from two directions by one light source 504, so that the number of light sources 504 can be reduced, resulting in reduced production cost of the lighting device 500.
Incidentally, in the lighting device 500 described in Japanese Patent Laid-Open Publication No. 2002-185708, light emitted by one light source 504 enters from one end of the light guide 502, and is guided through the light guide 502. As a result, intensity and chromaticity vary between light emitted from around one end of the light guide 502 and light emitted from around the other end. Consequently, in an image reading apparatus using the lighting device 500, images obtained by reading documents have low color reproducibility.